1. Field of the Invention
This invention relates generally to hybrid personal flotation devices and in particular to flotation devices having both a mass of buoyant material and an inflatable buoyancy chamber.
2. Description of the Prior Art
In designing flotation devices for use in connection with boating or aviation, the United States Coast Guard and Underwriters Laboratory establish the standards by which the flotation devices are approved for the marketplace. Consequently, no matter how effective a flotation device may be, if it does not meet the Coast Guard or Underwriters Laboratory's standards, its marketability will be extremely limited.
One of the Coast Guard requirements is that there be a minimum buoyancy of 151/2 pounds for an adult life vest or jacket, noting that previous studies have shown that 95% of the adult male population requires less than 12 pounds of buoyancy to remain afloat.
In the past, some life jackets (i.e. with sleeves) have been manufactured and sold which include both fixed or inherent buoyancy (i.e. foam or similar materials) and a provision for supplementing that buoyancy with, for example, air inflation provided through a tube by the wearer. However, in so far as is presently known, the amount of inherent buoyancy in such flotation devices was typically on the order of 151/2 pounds or greater, which is the minimum buoyancy standard set by the Coast Guard.
One of the major disadvantages of having a large amount of inherent buoyancy in a flotation device is that the mass of material required to provide the inherent buoyancy increases the bulk of the flotation discomfort.
In addition, prior art personal flotation devices were constructed such that the entire flotation device inflates. Therefore, to allow for the expansion of the buoyancy chamber, it was necessary for the material covering the buoyancy chamber to have a sufficient amount of extra material to allow for the complete expansion of the buoyancy chamber. This extra material also added to the bulk of the flotation device.
The present invention addresses the problems associated with the prior art flotation devices and provides for a hybrid personal flotation device which includes a minimal amount of inherent buoyancy plus a residual buoyancy from an inflatable buoyancy chamber to provide the required buoyancy as set by either the United States Coast Guard, Underwriters Laboratories or other organizations. In addition to the residual buoyancy of the buoyancy chamber, the buoyancy chamber also provides supplemental buoyancy to exceed the required buoyancy standard.